Free Radicals and Singlet Oxygen
Free radicals are formed when weak chemical bonds split. Free radicals are very unstable and react quickly with other compounds, trying to capture the needed electron to gain stability. Generally, free radicals attack the nearest stable molecule, “stealing” its electron. When the “attacked” molecule loses its electron, it becomes a free radical itself, beginning a chain reaction. Once the process started, it cascades, resulting in the disruption of a living cell. Internally, free radicals damage tissues and can adversely affect the body’s immune system. They weaken and can destroy cells and the DNA in the cells.
Oxygen is an element and a vitally important substance for life on earth. Living organisms need oxygen for most, if not all, for their cellular functions. On the other hand, oxygen produce metabolites that are toxic and potentially lethal to the same cells. Being reactive and chemically unstable, reactive oxygen species (ROS) are the metabolites that initiate reduction and oxidation (redox) reactions under physiological conditions. Oxygen in its excited singlet state (1O2) is the important intermediate in such reactions.
Singlet oxygen is linked to oxidation of LDL cholesterol and resultant cardiovascular effects. Polyphenol antioxidants can scavenge and reduce concentrations of reactive oxygen species and may prevent such deleterious oxidative effects.
Video on oxidative stress, free radicals, & antioxidants/Katie Rose: